#include <stdio.h>
#include <math.h>
int main() 
{
	double a ,b,c,s,area;
	a = 3.67;
	b = 5.43;
	c = 6.21;
	s = (a+b+c)/2;
	area=sqrt(s*(s-a)*(s-b)*(s-c));
	printf("a=%f\tb=%f\t%f\n",a,b,c);
    printf("area=%f\n",area);
    return 0;
	
}